Expansive bit



(No Model.)

B. H. FOWLE. BXPAN-SIVE BIT. No 594,615. Patented Nov. 30, 1897.

[N VEN T OR 'UNTTnn STATES Enron.

PATENT v EXPANSIVE BIT.

SPECIFICATION forming part of Letters Patent No. 594,615, dated November 30, 1897.

Application filed January 27, 1897- Serial No. 620,963- Nojnodeh) To all whom it may concern.-

Be it known that I, BERNARD H. FowLn, a citizen of the United States, residing at Spokane, in the county of Spokane and State of Washington, have invented certain new and useful Improvements in Expansive Bits; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention has reference to a novel construction in an expansive bit; and it consists in the features of construction hereinafter fully described and specifically claimed.

In theaccompanying drawings, forming a part of this specification, Figure 1 is a perspective view of the expansive bit constructed in accordance with this invention. Fig. 2 is a perspective view with the cutter removed, and Fig. 3 is a perspective View taken from the under side of the cutter.

Referring now to said drawings, 1 indicates the standing part of the bit, which is provided with a screw-threaded stem 2, upon which is situated a coupling-sleeve 3. The end of the stem 2 is beveled at its end, and the beveled end is provided with a rib 4:. The shank 5 is provided with a beveled end 6, having a groove 7, and is so constructed that it fits upon the end portion of the stem 2. This end portion of the shank is screw-threaded, so that the coupling-sleeve 3 can be screwthreaded upon the end portion of the shank and stem to couple the same. In this wayit is seen that the bit can be used with either a long or short shank, which can be readily interchanged. This is useful in various cases where it is desired to bore a hole adjacent to the obstruction which does not allow the turning of the brace. noted that the short bit can be inserted behind the obstruction, for instance, and have the shank coupled with the same from the outside. There are a variety of cases wherein this would be useful, as it is obvious to one skilled in the art. The standing portion 1 of the bit has a flat side, which is provided with a dovetail guide 8. In the bottom of this guide is a groove 9, while at the end of the said groove are lugs 10. Fastened to the lugs 10 is an adj usting-screw 11, that turns firmly therein and which is provided with a milled In a case of this kind it is finger-piece 12 for turning the same. It is noted that the adj listing-screw 11 projects beyond the inner wall of the guide 8 a sufficient distance to engage a screw-threaded groove 13in the inner face of the cutter 14:. This cutter 14 fits within the dovetail guide 8 of the bit, and the parts are so made that this cutter fits nicely therein and in close contact with the walls of the guide, while the relation between the adjusting-screw 11 and the screw-threaded groove 13 of the cutter is such that these parts are in close contact. The cutter 14: is provided with a scale on its outer face, so that the size of the bit can be nicely regulated. One end of the cutter or the end adjacent the finger-piece 12 is notched or cut away, as shown at 15, so that it receives the projecting portion of the thumb-piece,whereby the cutter can be moved to stand entirely within the standing part of the bit. It is further noted that the thumb-piece 12 projects beyond the outer face of the cutter, so that it can be operated at all times.

It is apparent from the foregoing description that a bit of this construction can be manipulated quickly and readily and without the use of a screw-driver or other instrument, since the thumb-screw serves to allow the cutter to be moved laterally. It is also noted that owing to the motion of the bit in cutting the strain upon the cutter is at the extremity, so that it has a tendency to retard that end and consequently to move the other end forward. This forces the dovetail sides of the cutter against the dovetail sides of the guide, so that the cutter is held with additional force, while it relieves it from the longitudinal strain, so that the screw-threaded portion of the cutter and the adj usting-screw are relieved of strain to avoid the possibility of ,stripping or even of the screw turning and thus changing the gage of the cutter. The direction in which the bit turns also serves to prevent friction caused by the shavings passing out across the face of the bit and from turning the screw by rubbing against the milled head thereof, since it is seen that this side of the bit is always turning away from instead of against the rising shavings or chips, as is obvious. It is also noted that the coupling-sleeve 3 is not large enough to ma terially interfere with the removal of the chips and shavings, and that also the device provides an inexpensive, practicable, and durable expansive bit.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

The combination with a standing part of a bit having a guide, a groove in the rear side of said guide, a lug at the end of said groove, and an adjusting-screw mounted upon said lugand provided with a finger-piece, of a cutter moving in said guide and provided on its inner face with a screw-threaded groove to engage the said adj Listing-screw, and the notched end of said cutter adjacent said finger-piece. In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

BERNARD H. FOWLE. \Vitnesses:

T. M. GROVE, D. H. DWIGHT. 

